1. Field of the Invention
The present invention relates to an incision tool that is used when a narrowing portion developed in an esophagus is incised.
Priority is claimed on Japanese Patent Application No. 2007-144874, filed May 31, 2007, the contents of which are incorporated herein by reference.
2. Description of Related Art
Conventionally, a method in which a balloon is used is known as a method of treating a narrowing portion developed in an esophagus. However, a treatment method which uses a balloon has the drawback that it is necessary in a large number of cases to perform repeated enlargement operations over a period of several weeks resulting in a lengthy period of treatment.
Because of this, a treatment method that uses an incision tool (see Japanese Utility Model Application No. 5-15918) to incise a narrowing portion of an esophagus by exposing wires on an outer side of a sheath, and then supplying high-frequency current to these wires has been proposed as one method of performing early treatment on an esophageal narrowing portion.
However, the following problems remain in the incision tool which is used in the aforementioned treatment method and which is disclosed in the aforementioned Japanese Utility Model Application No. 5-15918.
That is, in this incision tool, as a precondition, an operating unit that is manipulated by an operator is operated so that the wires that are connected to the operating unit are pushed out towards their distal end side, resulting in the exposed portion of the wires which are exposed on the outside of the sheath expanding outwards. However, at this time, conventionally, the distal end sides of the wires which should have stopped inside the sheath end up shifting towards the distal end side of the sheath. Because of this, it becomes impossible to farther expand the exposed wire portions to a desired shape, and consequently, the problem arises that a narrowing portion cannot be incised satisfactorily.